A wide variety of devices for feeding plant fertilizer to a continuously flowing stream of water are known. Such devices are used, for example, for fertilizing and sprinkling lawns and gardens. The fertilizer concentrate may be supplied in either solid or liquid form. All feeders include means for gradually feeding a solution of the fertilizer to the main stream of water as it passes on to the dispensing head of a sprinkler or sprayer. If the fertilizer is supplied in solid form, means must be provided for dissolving the solid material, either gradually as the solution is continuously fed to the main stream of water or as a batch-making step to be completed prior to feeding of the solution to the main stream. If the fertilizer is supplied as a concentrated solution, means are sometimes provided for diluting the solution prior to feeding to the main stream of water.
Generally, liquid fertilizer feeders include a removable or otherwise refillable container below the main channel body of the apparatus and by aspirating or other means cause the fertilizer solution to flow upwardly to the main stream of water. Mechanisms and structures, such as restricted passageways, may be provided to control the rate of flow of the solution to the main stream. Over long periods of use, small orifices tend to become partially or totally clogged.
The water sprayer of Wenzel U.S. Pat. No. 2,737,414 is an example of a fertilizer dispenser in which the base reservoir 4 is partly filled with solid material which is gradually dissolved by water flowing into the reservoir through a small passageway 26. The solution is then educted by suction created at nozzle tip 22 where it is incorporated in the water spray.
The liquid proportioning device of McNair U.S. Pat. No. 4,068,681 is an example of a feeder wherein solid fertilizer is dissolved as a first step in the operation of the feeder after which flow of the solution to the main stream of water is automatically started. This device, and the injector of Dulger, U.S. Pat. No. 3,421,738, employs rather complicated structures for dissolving and proportioning the flow of the fertilizer solution.
The liquid fertilizer feeder of the invention herein described is designed for connection in a lawn or garden hose for dissolving solid fertilizer, preferably in granular or powder form, at a controlled rate and supplying a dilute solution to a suitable sprinkler or sprayer for dispensing to the desired area. An object of the invention is to provide an improved device of this character which imposes minimum pressure loss so that water at essentially supply pressure may be continuously provided for the proper operation of the sprinkler or sprayer. An important object is to provide such a feeder wherein soluble fertilizer is supplied in disposable cartridges and a metering orifice is provided for controlling the rate of flow of water from a side branch stream into the supply body of fertilizer within the cartridge with means for conducting the solution back to the main stream of water whereby a continuous proportionate feeding of the liquid fertilizer is achieved. A feature of the design of the apparatus resides in the provision of the metering orifice in the cartridge container so that a new metering orifice element is put into use with each replacement of the solid fertilizer cartridge to ensure metering accuracy. Conveniently, the metering orifice and outlet solution apertures are provided in the closure of the cartridge.
Another object of the invention is to enhance the convenience of use of the feeder by locating the solid fertilizer supply on the top of the feeder, permitting access for replacement of the fertilizer cartridge while the feeder is resting upon the group or other surface. To this end, a removable watertight dome is provided as a cover for the fertilizer cartridge. An important feature of this arrangement is the provision of an air vent valve at the top of the dome to ensure against the accumulation of air which, when compressed under the influence of full water line pressure, could present a hazard in the event that the dome is not securely replaced upon the base of the feeder.